MEASUREMENT OF VISCOSITY USING VISCOMETER

&

MEASUREMENT OF TAPER ANGLE USING SINE BAR

Presented by

N.Vinayaga Muruga Pandy & S. Santhosh

Research scholar

MEASUREMENT OF VISCOSITY USING VISCOMETER

To determine the kinematic and dynamic viscosity of given oil sample using Redwood

viscometer.

Aim of the Experiment

Principle used

• Newton’s law of viscosity

Shear stress is directly proportional to velocity gradient

•Viscosity of fluids is inversely proportional to temperature

1. Redwood viscometer apparatus 2. Digital thermometer-2 Nos 3. 50 ml and 500 ml beaker 4. Oil sample 5. Temperature controller –Energy Regulator type

Apparatus required

Procedure

1.Pour the oil sample into the cup through a filter. Pour water into the bath.

2. Heat and stir the viscometer water bath to a few degrees above the desired test temperature.

3. Stir the sample during the preliminary period, e.g. by means of the ball valve closing the bottom of the jet by suitable means but do not stir the sample during the actual determination.

4. Control the temperature of the bath such that the oil sample is maintained at the test temperature.

5. When the temperature of the sample has become quite steady at the desired value, maintain the oil level up to the indicated level, by allowing the sample to flow out of the cup.

Procedure6. Place the oil cup -cover which shall be slightly warmed.

7. Place a clean and dry standard 50ml flask centrally below the jet. Do not insulate the flask.

8. Lift the bob so that the oil drains through the orifice and simultaneously start the time recorder. Suspend the bob valve from the clip supporting the oil-cup thermometer by means of the hook.

9. Stop the time recorder at the instant the sample reaches the graduation mark of the 50ml flask and note the final readings of the oil cup thermometer.

10. If the temperature of the sample in the oil-cup varies more than 0.5°C, then repeat the experiment.

Calculation Since the instruments used are of standard dimensions, kinematic viscosity

of the flowing oil in centistokes can be calculated from the time taken by the oil to flow through the standard orifice of the instrument with the help of the following equation.

Plots

1. Kinematic viscosity versus Temperature 2. Dynamic viscosity versus Temperature

MEASUREMENT OF TAPER ANGLE USING SINE BAR

To determine unknown angle using sine bar.

Aim of the Experiment

Principle used

Trigonometry

Sin ɵ = Opposite side / Hypotenuse

[A] [B]

1. Sine bar2. Surface plate3. Dial indicator,4. Slip gauges.5. Vernier height gauge

Apparatus required

Procedure

1) Surface plate is placed on a horizontal surface.2) Build up slip gauges of a proper height by wringing.3) Place one of the cylinders of sine bar on surface plate and other on slip gauges.4) Dial indicator is set at one end of the component and moved to the other end.5) Note the deviation in dial reading.6) Again slip gauges are so adjusted that dial indicator reads zero deviation across the work surface if deviation is ‘δh’ over length ‘l1’, change slip gauge height by (δh x L / l1)Where L is standard sine bar length7) Again take dial indicator reading to assure zero deviation.8) Read slip gauge height and perform calculation

CalculationReading:-• A] h= L=• B] h1= h2= L=

Calculations:-•  A] Sin θ = h/L•  θ = Sin-1 ( h/L )•  θ =

• B] Sin θ = h1-h2 / L•  θ = Sin-1 ( h1-h2 / L)•  θ =

References

1. http://en.wikipedia.org/wiki/Viscosity2. http://en.wikipedia.org/wiki/sinebar3. http://en.wikipedia.org/wiki/

Temperature_dependence_of_liquid_viscosity4. 'Numerical Methods for Engineers' by Steven C Chapra and Raymand P

Canale.